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Highest Speeds on Sidewinder/Thundercat

Fleecer

Lifetime Member
Joined
Jun 13, 2014
Messages
1,091
Age
53
Country
USA
Snowmobile
2019 SRX
With some of us owning Sidewinders for 6 seasons now, I wanted to start a thread on Max Speeds attained thus far. It seems ever year we get faster and faster, so I thought it prudent to share our results here.

I'm not interested in starting a bashing fest. If some want to lie, so be it, however I ask that everyone is honest. Here are the rules:

1. Speeds can be speedo, GPS, or radar gun. Please state how you recorded speed.
2. Indicate distance and terrain. For example, 1/4 mile on ice, or asphalt etc.

A lot of time and research goes into tuning and we all understand that. If you rather not share your setup, that's fine. If you don't mind sharing, please list tune/clutching etc, as I'm sure many could learn here. In the end, I think this could be a productive post, as people can compare performance, see what others are doing, and perhaps improve their sleds.

So....here we go, I'll start. Took my last ride of the year today, temps were low 30s F, and conditions a little soft. The local club groomed last night, but it never went above freezing, so things didn't setup hard, however trails were smooth.

My sled is setup for trail riding with medium windshield and I don't run studs. Sled was factory height, not tied down or anything. On my way home, I was rolling about 100mph, came up to a long stretch with good vision, and held it WOT for about .5 miles. Had my GPS in my pocket it recorded 141 mph. My best all winter was 146 mph while trail riding.

Start sending those numbers....
 
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16/17 season 122mph (Speedo)..it was in Canada on powder with 2" crust over that. Long pull with what I think we're bad conditions
I managed 115 (Speedo) this year on good hard packed lake. I'm guessing with shut down probably .5 mile. Maybe more?!? Idk....
Same time & place, raced two Polaris 850's, SRX, XTX and 900t.
Was able to beat all of them from the dig & on.... Except the xtx, one time,as he jumped me and I couldn't reel him in.
My point to bring up others is....I'm satisfied with what my sled did against others in real world runs. Stock tune....
 
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As posted earlier local radar run on lake I was able to hit 91.35 mph on snow pack lane 500 ft. I went back out to same spot and marked off 1000 ft on the ice strip portion of the lane. Had to start out on snow then moved onto ice. After many runs I could only mustard up 118 mph and held her open pass the 1000 ft and couldn’t get anymore speed. Actually slowed down when I was on the snow. When I bought it new I was able to hit 120 gps on hard packed gravel road with studs only. I have CAI Rockerdan style, thunder products orange clutch springs and 33/35 reverse helix, stm clutch weights and SSI speed shop exhaust. Power comander V. 96 Gold Digger studs.
 
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With some of us owning Sidewinders for 6 seasons now, I wanted to start a thread on Max Speeds attained thus far. It seems ever year we get faster and faster, so I thought it prudent to share our results here.

I'm not interested in starting a bashing fest. If some want to lie, so be it, however I ask that everyone is honest. Here are the rules:

1. Speeds can be speedo, GPS, or radar gun. Please state how you recorded speed.
2. Indicate distance and terrain. For example, 1/4 mile on ice, or asphalt etc.

A lot of time and research goes into tuning and we all understand that. If you rather not share your setup, that's fine. If you don't mind sharing, please list tune/clutching etc, as I'm sure many could learn here. In the end, I think this could be a productive post, as people can compare performance, see what others are doing, and perhaps improve their sleds.

So....here we go, I'll start. Took my last ride of the year today, temps were low 30s F, and conditions a little soft. The local club groomed last night, but it never went above freezing, so things didn't setup hard, however trails were smooth.

My sled is setup for trail riding with medium windshield and I don't run studs. Sled was factory height, not tied down or anything. On my way home, I was rolling about 100mph, came up to a long stretch with good vision, and held it WOT for about .5 miles. Had my GPS in my pocket it recorded 141mph. My best all winter was 146mph while trail riding.

Start sending those numbers....
What power level are you set at?
Gearing?
 
Saw 120 on my thundercat speedo on a railbed hardpack
 
126 speedo on hard packed snow trail across pond! Excellent traction with no spinning! Seen much better on ice, but not worth saying because of spinning with worn stud tips!
17 LTX-LE, Max Spool 16 3 bar tune,BOV, 22T, 1 1/4” track, 144 Gold diggers 1.325” down middle. Stock springs on both clutches with modified stock weights.

Was hoping to better that this year by adding MS17 with SQ2.5”, but did not go as planned! Maybe next year.
 
What power level are you set at?
Gearing?

Here's what I run:
Turbo Dynamics Jukebox Header Tunes (Usually MS-17)
SQ 2.5
CAI
Big gears
FLEECER custom clutching (Sorry, can't share more.)
 
With some of us owning Sidewinders for 6 seasons now, I wanted to start a thread on Max Speeds attained thus far. It seems ever year we get faster and faster, so I thought it prudent to share our results here.

I'm not interested in starting a bashing fest. If some want to lie, so be it, however I ask that everyone is honest. Here are the rules:

1. Speeds can be speedo, GPS, or radar gun. Please state how you recorded speed.
2. Indicate distance and terrain. For example, 1/4 mile on ice, or asphalt etc.

A lot of time and research goes into tuning and we all understand that. If you rather not share your setup, that's fine. If you don't mind sharing, please list tune/clutching etc, as I'm sure many could learn here. In the end, I think this could be a productive post, as people can compare performance, see what others are doing, and perhaps improve their sleds.

So....here we go, I'll start. Took my last ride of the year today, temps were low 30s F, and conditions a little soft. The local club groomed last night, but it never went above freezing, so things didn't setup hard, however trails were smooth.

My sled is setup for trail riding with medium windshield and I don't run studs. Sled was factory height, not tied down or anything. On my way home, I was rolling about 100mph, came up to a long stretch with good vision, and held it WOT for about .5 miles. Had my GPS in my pocket it recorded 141mph. My best all winter was 146mph while trail riding.

Start sending those numbers....
Impressive Fleece!!
 
Impressive Fleece!!

Thanks DMC, I appreciate the kind words, especially coming from a fast guy like you.

Is your season over, or are you still at it?
 
Here's what I run:
Turbo Dynamics Jukebox Header Tunes (Usually MS-17)
SQ 2.5
CAI
Big gears
FLEECER custom clutching (Sorry, can't share more.)
Well your GPS speeds will be hard to beat or even come close to, and you have given us some insight as to how!

SRX with stock 1” track and no studs, on snow, not ice, with lot’s of power and well tested clutching and gearing!
You have as good a recipe for speed, as you have the testing spot, being from the County with so many long straight RR beds for testing needs! Fun factor X2 for you and that reliable and fast 4 stroke! Yeah, SRX’s rule on top!
 
2018 RTX. Stock gearing, Max Spool 16 2 bar tune.

I've seen 125 on the speedo multiple times on a groomed forest road near my house. I believe it is out of gear at that point.
 
Well your GPS speeds will be hard to beat or even come close to, and you have given us some insight as to how!

SRX with stock 1” track and no studs, on snow, not ice, with lot’s of power and well tested clutching and gearing!
You have as good a recipe for speed, as you have the testing spot, being from the County with so many long straight RR beds for testing needs! Fun factor X2 for you and that reliable and fast 4 stroke! Yeah, SRX’s rule on top!

Motorhead, you bring up a valid point, and upon further thought, perhaps my ignorance has shunned some from posting. Thank you for bringing this to my attention. The purpose of this post is to share information and communicate ideas in making our snowmobiling experiences better as a community.

I edited my initial post, as I want to invite people to contribute, not scare them away.
 
2018 RTX. Stock gearing, Max Spool 16 2 bar tune.

I've seen 125 on the speedo multiple times on a groomed forest road near my house. I believe it is out of gear at that point.

Opinions will vary here, but I've seen 128 speedo with stock gears. A little trick is to mark your sheaves with a felt sharpie. You can see how high it shifts by how much the belt cleans the mark. Stock primary, the belt should clean all but 1/8th of an inch from the top. Secondary is a little easier to shift fully and will clean the whole sheave.

In the attached pic, I had marked a line across the whole sheave. The belt cleaned it all.
 

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20 S-TX GT, new to me this year. I bought it with 100 miles on it. I added Max Spool 16 w/ dalton weights and 187 studs, after riding it a few hundred miles, everything else is stock.

125 on spedo a few times, maybe maxed out on the gearing as the lake conditions were perfect and it gets there pretty easy. I didn't get to try it before I added the tune. I thought that was pretty good given the 146" track and the 2-up seat.... :cool: Been riding fast sleds since I was a teenager, this is my first boosted sled and I have to say it has some serious fun factor.

Those running the MS16, does the 3 BAR, blow off valve make much difference in speed #'s. Considering adding these for next season.
 


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